As the UK faces the highest number of COVID-cases since July, health authorities tracking the various variants of the virus have identified a new and potentially more infectious subvariant in at least six per cent of samples sequenced.
While the Delta variant remains the dominant one in the UK, the AY.4.2 subvariant, sometimes called “Delta Plus”, is no spreading and contains mutations that may give it survival advantages. However, it is not yet considered a “variant of concern”.
First identified in July, it contains two mutations – Y145H and A222V – that have been found in other coronavirus lineages. Professor Francois Balloux, director of University College London's Genetics Institute, told the BBC that this was “potentially a marginally more infectious strain” that is likely to be up to 10 percent more transmissible.
"It's nothing compared with what we saw with Alpha and Delta, which were something like 50 to 60 percent more transmissible. So we are talking about something quite subtle here and that is currently under investigation.”
“New sublineages of Delta are regularly identified and designated. One recently designated sublineage is AY.4.2,” notes the UK Health Security Agency (HSA) in its latest technical briefing document.
“A Delta sublineage newly designated as AY.4.2 is noted to be expanding in England. It is now a signal in monitoring, and assessment has commenced; there are also small numbers of new cases of Delta with E484K and Delta with E484Q,” it adds.
This variant had also been identified in the US and in Denmark.
Government data showed there were 49,156 new cases of coronavirus in the UK on Monday, up from 45,140 on Sunday, and the highest daily total since July 17.